[openssl-dev] Null pointer dereferences?

[Zubin Mevawalla]

I was curious if these were real null pointer dereference issues?

CodeAi, an automated repair tool being developed at Qbit logic,
suggested a couple of if-guards as fixes.

The first was in crypto/async/async_wait.c on line 157. `prev` is
assigned to NULL on 144, and it doesn't look like it is assigned to
anything in the while loop. Access to the field `next` from variable
`prev` thus results in a null pointer dereference.

diff --git a/crypto/async/async_wait.c b/crypto/async/async_wait.c
--- a/crypto/async/async_wait.c
+++ b/crypto/async/async_wait.c
@@ -154,7 +154,9 @@ int ASYNC_WAIT_CTX_clear_fd(ASYNC_WAIT_CTX *ctx,
const void *key)
                 if (ctx->fds == curr) {
                     ctx->fds = curr->next;
                 } else {
-                    prev->next = curr->next;
+                    if(prev) {
+                        prev->next = curr->next;
+                    }
                 }

                 /* It is responsibility of the caller to cleanup before calling


The second fix was in ssl/statem/statem_srvr.c on line 1442 having
seen a path through the control flow where access to the field
`pre_proc_exts` from variable `clienthello` results in a null pointer
dereference. On line 1243 if `clienthello` is NULL then control jumps
to line 1440, and `clienthello` is dereferenced on line 1442 without
having being assigned.

diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -1439,7 +1439,9 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL
*s, PACKET *pkt)
  err:
     ossl_statem_set_error(s);

-    OPENSSL_free(clienthello->pre_proc_exts);
+    if(clienthello) {
+        OPENSSL_free(clienthello->pre_proc_exts);
+    }
     OPENSSL_free(clienthello);

     return MSG_PROCESS_ERROR;

Could I submit these as patches if they look alright?

Thanks so much,

Zubin